Measurement of biometric data may be useful to process a viewer's reaction to media content. For example, the amount a viewer's heart rate increases during a thrilling scene of a movie may reflect how thrilled the viewer was caused to be by the scene. However, some biometric measurements may not be useful in processing a viewer's reaction to media content. As an example, during the same thrilling scene of the movie, measuring how much a viewer is smiling or frowning will not reflect how thrilled a viewer is. Accordingly, such biometric measurements may act as noise when control circuitry seeks to determine, based on a totality of biometric measurements, a viewer's reaction to a given portion of media content. Moreover, it is inefficient to capture biometric measurements that are not helpful in processing a viewer's reaction to a given portion of media content.